| 摘要 |
<p>A welded joint in which an area ratio of ferrite structure in HAZ thereof is 20-100 %, the rest comprising one or not less than two kinds out of bainite structure, martensite structure, pearlite structure and residual austenite structure. In another embodiment, in addition to the above, the carbon equivalent of a steel plate used for a welded joint is limited to not more than 0.275. The propagation speed of a fatigue crack in HAZ is thereby minimized to improve the fatigue strength of the joint in a welded state.</p> |
